1. Field of the Invention
The present invention relates to a network load testing method in which loads are imparted to a network such as a local area network (LAN) through data transfer on the network.
2. Description of the Related Arts
The network load testing is carried out before the shipment of the apparatuses or after the establishment of the network, the method including imparting loads to network adapters mounted on the apparatuses making up the network or to network transmission lines, to thereby judge the network performances.
FIG. 5 is a view for explaining a method for testing a network load in the prior art. In FIG. 5, apparatuses A, B are connected to the network such as LAN, etc. Each of the apparatuses A, B comprises a processor module (CPU) 10 for controlling a communication, and a network adapter (interface board) 20 for transmitting and receiving data. The network adapter (interface board) in the case where the network is the LAN is a so-called LAN card. The network adapter 20 comprises a transmitter 21 and a receiver 22. The processor module 10 is connected to the network adapter 20 via a LS bus 20. A test program for testing the network load is loaded to both the apparatuses A, B as structured above, and the test program is executed in both the apparatus, whereby the method for testing the network load is executed.
Data are transferred between the apparatuses A and B via the network. Specifically, data transmitted from a transmitter 21A of the apparatus A are received by a receiver 22B of the apparatus B via the network, and data transmitted from a transmitter 21B of the apparatus B are received by the receiver 21A of the apparatus A via the network. While the test for loading the network is executed, the data are transferred in both directions of the apparatuses A, B. As the data transfer from the apparatus B to the apparatus A is same as the data transfer from the apparatus A to the apparatus B, hereinafter, the data transfer from the apparatus A to the apparatus B will be explained. Furthermore, a communication as explained below is one (inter-task communication) between programs which is executed by the processor module 10 and network adapter 20.
According to a transmission start command from a processor module 10A of the apparatus A, the receiver 21A of the apparatus A starts transmitting test data in packet unit. The receiver 22B of the apparatus B counts the number of reception (the number of packet), while receives the test data transmitted in sequence from the transmitter 21A.
When the receiver 22B receives data of the predetermined number of packets (for example, 128 packets), it notifies a processor module 10B of the apparatus B of reception completion by way of a LS bus 30B (communication {circle around (1)} of FIG. 5). The processor module 10B notifies the processor module 10A of the apparatus A of the reception completion by making use of a communication a path other than a test targeting network (for example, RS232C, or the like) (communication {circle around (2)} of FIG. 5). As the network is a target of the test, it is not utilized for an inter-task communication. According to a notification of the reception completion, the processor module 10A notifies a transmission stop command the transmitter 21A by way of the LS bus 30A (communication {circle around (3)} of FIG. 5). Furthermore, when the transmitter 21A stops the transmission, it notifies the receiver 22A of a transmission stop.
On the other hand, when the receiver 22A of the apparatus A receives the test data from the transmitter 21B of the apparatus B, as described above, the receiver 22A notifies the processor module 10A of the reception completion (communication {circle around (4)} of FIG. 5).
When the receiver 22A notices the reception completion and receives a transmission stop, the receiver 22A notifies the processor module 10A of a transmission and reception completion by way of the LS bus 30A (communication {circle around (5)} of FIG. 5). Thus, 1 cycle of the test is ended. Furthermore, the receiver 22A notices the transmission and reception completion, thereby becoming a reception READY condition in a next test cycle.
FIG. 6 is a timing chart of a method for testing a network load in the prior art. FIG. 6 shows the timing chart of the transmitters 21A, 21B and receivers 22A, 22B in the respective apparatuses A, B. Encircled digits in each timing chart indicate communication time of each communication. Accordingly, for example, even when a reception of the test data of the receiver 22B of the apparatus B is ended, the transmitter 21A of the apparatus A continues to transmit, and stops a transmission by the reception of the transmission stop notice.
In FIG. 5 or 6, when the processor module 10A receives the notice of the reception completion from the receiver 22A, the processor module 10A transmits the reception READY condition notice for starting a next test cycle to the apparatus B. The transmitter 21 starts transmitting after a receiver 22 of a mating apparatus becomes in a reception READY condition. In more details, the processor module 10A utilizes a communication path different from the above testing network, and transmits the reception READY condition notice to the processor module 10B (communication {circle around (6)} of FIG. 5). The processor module 10B transmits a transmission start command to the transmitter 21B (communication {circle around (7)} of FIG. 5).
When the transmitter 21B receives the transmission start command, the transmitter 21B restarts transmitting the test data. In this manner, in the method for testing the network load in the prior art, one apparatus does not transmit the test data until the other apparatus becomes in the reception READY condition. Namely, both the apparatuses are synchronized with each other, while the data are transmitted and received, and during a predetermined test time, the test cycle is repeated.
However, the above method for testing the network load in the prior art has the following drawbacks:
First, during a span between the reception of the test data and a next reception in the test cycle, the inter-task communication for synchronizing the apparatuses with each other (the respective communications {circle around (1)}→{circle around (2)}→{circle around (3)}→{circle around (4)}→{circle around (5)}→{circle around (6)}→{circle around (7)} of FIGS. 5 and 6) intervenes, and a time which is required for the inter-task communication is relatively long. For this reason, a transmission and reception period during the test cycle is relatively short, and also the cycle of the test cycle is prolonged. Therefore, it is impossible to give a high load which leads out a limit of performance to the network adapter.
Second, as the communication path (for example, RS232C, or the like) different from the test targeting network is necessary for the inter-task communication between the apparatuses, a test environment and test facility are troublesome.
In this manner, in the conventional method for testing by synchronization in which the transmission does not start until a mating side becomes in the reception READY condition in each test cycle, a certain time is required for the inter-task communication. Therefore, the high load is not given to the network (network adapter and communication path), and also it is necessary that another communication path is prepared.